The invention relates to a method for the direct injection of fuel and a device for implementing the method.
In the general state of the art, the fuel valve consists of a partly open and partly closed nozzle cut off from the combustion chamber by a needle to prevent dribbling. The injection nozzle and the inlet valve are separate and are also fitted individually and separately from each other. As the valves are usually fitted vertically to the cylinder, the injection nozzle must necessarily be arranged between the inlet and exhaust valves. It is known that the combustion chamber in the piston must therefore be specially shaped to ensure the proper atomisation of the fuel. It is known that a method of doing this is to make the piston head in the shape of a heart or pan in order to give the air in the combustion chamber a spin with the aid of air guides so as to improve the atomisation of the fuel.
The purposes of the inlet valve and the atomisation nozzle are different. Whereas the valves are designed to let the fuel-air mixture in or the exhaust gases out, the atomisation nozzles are designed to admit the fuel into the combustion chamber and atomise it. The better the atomisation of the fuel in the combustion chamber, the better the combustion.
French patent specification No. 2,050,287 describes a fuel injection pump for a four-stroke engine in which the injection pressure may be obtained simply by pressing down the inlet valve in which the injection valve is centrally arranged. This arrangement cannot be transferred to the diesel engine because, in this method, the injection pressure is determined by the spring-loaded, chamberless injection valve. The stronger the pressure spring on the injection needle, the greater the spray pressure and the greater the pressure rise in the injection pump fitted outside the cylinder. FIG. 1 of the French patent specification is typical of four-stroke engines and can by no manner of means be transferred to diesel engines, since in the diesel engine the fuel must be sprayed in with the valve closed and not with it open as shown in FIG. 1 of the French patent specification.
French patent specification No. 1,554,337 describes a fuel injection device for a two-stroke engine in which the valve and injector are mutually separate and where there is no method of direct injection. In contradistinction, in the present invention the valve and the injector form an integral unit in which the valve is positively and stroke-controlled and a feature is that the fuel is directly injected.
U.S. Pat. No. 2,280,386 describes a combined cylinder with a poppet valve and a fuel injector, in which the fuel is not directly injected but must first be taken into an annular chamber and where the inlet valve and the injector do not form an inseparable unit. This publication contrasts with the present invention, according to which the valve and the injector form an inseparable unit giving direct fuel injection.